As Jon Price comments, this is a big screen version of the popular British situation comedy, set in the East End of London. A London Transport AEC Swift (probably more likely than a Merlin) is seen through the window of the local hairdressers, then in the same spot two Swifts turn out behind a passing AEC RT on route 1.
As Arthur (Wilfred Pickles)visits a jeweller, a Green line AEC RF passes two AEC RTs. Briefly seen is Bedford VAS1/Duple ORO 970D of Wrens Coaches (red/cream) bringing guests to a surprise party. for Ada and her husband Arthur. At the time Arthur and Ada are travelling aboard another RT seen crossing Westminster Bridge.